The present invention relates to azetidinol containing materials having one azetidinol moiety per molecule and reaction products prepared therefrom.
Acrylic polymers have been well known as vehicles for coating compositions as well as for pigment grind pastes used in formulating such coating compositions. They can provide tough, resilient and durable coatings with excellent aesthetic properties.
Small nitrogen ring containing materials such as aziridines have been used as modifiers for coating compositions such as those described above for sometime. For example, U.S. Pat. No. 3,290,417 to Christenson et al discloses that the overall properties of coatings based on interpolymers of hydroxyalkyl esters are greatly improved by the inclusion of a small proportion of acidic units in the polymeric vehicle and reacting these acidic groups with an alkyleneimine or a substituted alkyleneimine. A further example is U.S. Pat. No. 3,290,416 which discloses coating compositions containing polymerized alkyl methacrylates which have been modified to improve their properties by the inclusion of imine-reacted acidic groups.
Aziridines, however, despite their potential for improving the overall properties of coatings formulated with the polymers they modify, are highly reactive materials which have a number of attendant disadvantages. Their highly reactive nature makes them unstable and in addition they are highly toxic requiring special conditions for handling. The most commonly available forms, ethylene imine and proplene imine are low molecular weight materials which are so unstable, safe transportation is virtually impossible. Moreover they are highly toxic materials which may have carcinogenic side effects.
In addition, materials derived by reacting ethylene imine or proplene imine with carboxylic acids tend to undergo rearrangement to the corresponding amide under certain severe conditions like prolonged heating thereby reducing the yield of desired aminoester product. Further, their high reactivity often results in a small amount of homopolymer by-product formation. The homopolymer causes the final film to be hazy thus impairing the appearance properties of coatings prepared from these materials.
There is a need for a way to prepare modified acrylic polymers which have all of the beneficial properties of the aziridine modified materials but without the attendant disadvantages.